unable to send japanese characters with HTTP request

I am working on .net framework. I have an application in which i m sending an HTTP Request to another project. The attributes to be sent includes some japanese characters which i am unable to get at the decoding side. I am getting the variables through

request.GetServerVariable

I am encoding the messge through ascii encoding
It is a VC++ application and i m compiling it through MULTIBYTE character set. In this I cant use Unicode character set.